The present invention relates in general to shower pans, and more particularly, to a prefabricated under mud shower pan that allows for tiles of varying thickness to be installed on the interior surface of the shower pan, and for added protection against water migration.
Most shower pans are either custom-made or have a drain pipe already built into the shower pan. The problem with these is that it is difficult to install tiles in the interior surface of the shower pan. This can be due to several problems. First, some shower pans comprise curvatures that are not designed for placement of tile on them. Second, other shower pans have a drain pipe pre-installed in the shower pan so that if tiles were placed on the interior surface of the shower pan, they would not be flush with the drain pipe, making the horizontal floor area of the shower pan appear awkward. Third, custom-made shower pans with tiles pre-installed are limited to the tiles available to the manufacturer. Fourth, while it may be possible to glue tiles onto a shower pan, one cannot control the elevation of the tiles by floating cement over the surface of the shower pan, including the waterdam. Home builders or remodelers would not have the flexibility of installing tiles of their choosing, such as imported tiles, nor control the elevation of the tiles placed on the shower pan.
Various types of shower pans are known. U.S. Pat. No. 6,990,695 issued to Grayson describes a shower pan for mounting in a shower stall that includes a single integrally molded base with a drain hole. A sidewall extends upward from the base and completely surrounds the base. A lateral ledge extends outward from the sidewall and has an inner edge and an outer edge defining a surface therebetween for mounting a shower stall door track. An outer ridge extends upward from the outer edge of the lateral ledge and is in spaced-apart relation to the door track. Water flowing through cracks between the door track and the shower pan is prevented from escaping the shower pan by the outer ridge, which allows water to drain under the door track into the shower pan. However, due to the curvatures in Grayson, it is not possible to install tiles. Furthermore, Grayson is not designed to be used with a conventional drain pipe.
U.S. Pat. No. 6,003,169 issued to Davis, Jr describes a prefabricated, custom-built shower pan with a drain hole for use in a shower stall. The shower pan comprises an acrylic-based, solid surface upper layer; a polystyrene foam layer and a planar base layer with raised edges. The polystyrene foam layer is framed by the base layer and covered by the acrylic-based, solid surface upper layer. Also provided is a shower pan comprising an acrylic-based, solid surface upper layer; a base layer comprising a planar base with raised edges, a system of stringers, and a water dam. The stringers are substantially straight, horizontal wooden supports which collectively incline toward the drain hole. They are relatively evenly distributed within and adhere to the rectangular-shaped base. Each stringer has an incline on its upper surface, and one end abutting one edge of the base. However, Davis is a custom-built shower pan. It is not a shower pan that allows for a conventional drain pipe to be inserted in the drain hole such that the drain pipe rises approximately ½ to 2 inches above the horizontal surface of the shower pan, allowing for tiles of various thickness to be installed in a manner that the top of the tiles are flush with the top portion of the drain pipe.
U.S. Pat. No. 4,541,132 issued to Long describes a shower pan which forms a base of a shower stall. It has a one piece drain surface and is capable of being built in various sloping configurations. The shower pan is constructed of a top drain panel supported by graduated shims and perimeter strips which are in turn mounted on a planar foundation. Perimeter strips and graduated shims are secured to the foundation, concentrically spaced apart, surrounding a variably located drain opening. The top drain panel is cut to the same contour and size as the foundation and has a rear member, side members, and threshold members to provide lateral water barriers. Kerfed break lines in the top drain panel permit the panel to bend to form a basin like drain surface. The top drain panel is positioned and pressed down onto the shims at perimeter strips forming a drain basin with sloping panel sections defined by the kerfed break lines. A waterproof material such as hot mop tar is applied to the interior surfaces of the shower pan. An adhesive is then applied to all exposed surfaces and a finish covering such as ceramic tile or cultured marble is applied to the shower pan. The problem with Long is that it is comprised of separate pieces (side members and rear members) which create potential openings for water to escape, thereby requiring the need for a hot mop tar for waterproofing. Furthermore, the drain wipe does not rise up sufficiently high above the shower floor surface to allow for different tile sizes to be used, and the drain hole may not be suited for conventional drain pipes.
It is an object of the present invention to provide a one-piece shower pan without openings for water leakage, that is designed for easy installation of tiles of various thickness, having a drain hole designed to fit a conventional drain pipe such that the pipe rises anywhere from ½ inch to 2 inches above the shower floor surface to accommodate tiles of varying thickness so that the top surface of the tiles are substantially flush with the top portion of the drain pipe, and with an additional fin on the waterdam to prevent water migration outside the shower pan should water seep past the tile and cement. Other objects of the present invention will become better understood with reference to appended Summary, Description and Claims.